Slowly progressive leukodystrophy in an adolescent male with phosphoglycerate kinase deficiency

We report the case of an 18-year-old man with a phosphoglycerate kinase (PGK) deficiency who had slowly progressive leukodystrophy during adolescence. The patient had a history of severe neonatal jaundice, hemolytic crisis with rhabdomyolysis triggered by febrile viral infections, dysarthria, and intellectual disability during early childhood. Clumsiness in walking and writing became obvious at ∼10years of age. Evaluations performed by us on the 18-year-old patient confirmed the presence of pyramidal tract signs, increased muscle tone, and generalized dystonia. Brain magnetic resonance (MR) imaging revealed leukodystrophy in the periventricular white matter, posterior limbs of the internal capsule, dorsal pons, and middle cerebellar peduncles. Compared to MR images acquired at 9years of age, MR images acquired at 18years of age showed that the white matter atrophy had progressed. The PGK deficiency was diagnosed by identifying a known missense mutation in PGK1 (c.1060G>C) through comprehensive target capture sequencing and by observing low PGK activity in his red blood cells. The patient underwent a ketogenic diet for 2weeks, which we expected would increase adenosine triphosphate levels through sources other than the PGK-associated glycolytic pathway. The diet was not tolerated owing to the unexpected emergence of hemolysis. Hemolytic anemia, neurological dysfunction, and myopathy are often associated with PGK deficiencies. However, leukodystrophy as a symptom of PGK deficiency has not been reported previously. Our case highlights the progressive nature of the neurological complications related to PGK deficiencies. Therefore, long-term follow-up is recommended, even if neurological impairments are not obvious during childhood.